The mind has not merely made a discovery of external fact; it has altered its own character by the attempt to know external fact.

The mind has shown itself capable of grasping the incomprehensible; it has stood in the presence of the infinite and perceived it as finite; it has measured the unmeasurable and found dimensions.

The mind does not work by starting from universal principles and deducing particular consequences; it works the other way, by gathering up particular cases until the accumulated weight of them forces upon us recognition of a universal principle.

The mind, once expanded by a new idea, never returns to its original dimensions.

The mind itself is the seat of action. We do not act because we think, but we think because the possibility of action is always before us.

The mind of man has perforce been made analogous to a mirror, or to a vessel, which can be filled with the images or ideas of things external. But this is a most inadequate and false representation of what takes place in the mind when it is occupied with the pursuit of truth.

The mind is furnished with a set of instincts which seek out certain kinds of phenomena and are satisfied by the presence of these phenomena, just as the nutritive instincts are satisfied by food.